A NUV Analysis of RR Lyrae: Leveraging Archival Data and Preparing for Future Surveys

In the NUV, an RRLs flux can vary drastically during pulsation, with amplitudes up to 2.7 mag, driven by a high correlation between changes in effective temperature. At these shorter wavelengths, light curve morphology is highly sensitive to the slightest variation in fundamental parameters, such as metallicity. Therefore, a NUV light curve morphology analysis can offer numerous critical insights into underlying stellar astrophysics and pulsation. The unique UV properties of RRL can provide many fundamental tools needed in future UV missions. For instance, we currently face high uncertainty in measuring UV extinction; however, RRL can provide direct extinction measurements with minimal reliance on assumed extinction laws or prior optical and infrared maps. Unfortunately, to date, minimal studies of RRL in the UV have been conducted owing to the historical sparsity of available UV photometry in terms of both phase coverage and the span of RRL parameter space. This work presents the initial results from constructing the largest empirical database of UV time-series data of RR Lyrae to date (comprising >3000 sources, over an order of magnitude increase), which spans, for the first time, the entire range of period and metallicity. Our dataset is generated from an archival study of serendipitously observed Swift/UVOT photometry of field RR Lyrae. We present planned tools/calibrations to be created by utilizing this dataset (i.e., light curve templates, standard candle calibrations, photometric metallicities, etc.) and how these methods will directly influence upcoming UV-dominated missions, namely the Ultraviolet Transient Astronomy Satellite (ULTRASAT).